• Insects, Diseases and Abiotic Disorders in Southwest Forests and Woodlands

      DeGomez, Tom; Garfin, Gregg (College of Agriculture, University of Arizona (Tucson, AZ), 2015-11)
      Recent events in the forests of the Southwest, and across western North America, have prompted scientists to consider the role of climate variability in insect and disease cycles. Studies focusing on Arizona and other southwestern states point to multiple, interacting climate-related mechanisms that increase the propensity for forest mortality. Effects of insects on forests are complex, and species and site dependent. Many influences, such as drought, decreased precipitation, increased temperature, increased vapor pressure deficit, and increased stand density, combined in nonlinear and overlapping ways to create the recent and devastating pine bark beetle outbreaks in Arizona forests. Climate clearly plays a role in many, but not all, Southwest insect cycles. It is important that educators demonstrate the complexity of all of the interplaying issues, in order to communicate no false impressions of an “easy” or “one-size- fits-all” solution” for land managers.
    • A Summary of Livestock Grazing Systems Used on Rangelands in the Western United States and Canada

      Howery, Larry D.; Sprinkle, James E.; Bowns, James E.; Natural Resources & the Environment, School of; Animal Sciences (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2000-09)
      The objectives of this article are to provide an overview of the major grazing systems that have been used on rangelands in the western U. S. and Canada, to summarize the conditions under which they may be applicable, and to highlight examples from the southwestern U. S. when relevant.